EP1085675A2 - Power control method for broadcast messages - Google Patents

Power control method for broadcast messages Download PDF

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Publication number
EP1085675A2
EP1085675A2 EP00307590A EP00307590A EP1085675A2 EP 1085675 A2 EP1085675 A2 EP 1085675A2 EP 00307590 A EP00307590 A EP 00307590A EP 00307590 A EP00307590 A EP 00307590A EP 1085675 A2 EP1085675 A2 EP 1085675A2
Authority
EP
European Patent Office
Prior art keywords
signal
protocol
probe
equipment
transmitted
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP00307590A
Other languages
German (de)
English (en)
French (fr)
Inventor
Li Gang
Wang Liwa
Zhu Pengfei
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nokia of America Corp
Original Assignee
Lucent Technologies Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Lucent Technologies Inc filed Critical Lucent Technologies Inc
Publication of EP1085675A2 publication Critical patent/EP1085675A2/en
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04—TPC
    • H04W52/30—TPC using constraints in the total amount of available transmission power
    • H04W52/32—TPC of broadcast or control channels
    • H04W52/322—Power control of broadcast channels
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04—TPC
    • H04W52/30—TPC using constraints in the total amount of available transmission power
    • H04W52/32—TPC of broadcast or control channels
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • the present invention is generally related to a method for controlling adaptively the power of various messages broadcast by communication equipment to increase the likelihood that such messages are detected.
  • wireless communication systems comprise a plurality of communication channels through which subscribers of such systems communicate with each other and with the system.
  • a portion of a typical wireless communication system is shown in FIG. 1.
  • the wireless communication system of FIG. 1 depicts a cellular system comprising cells (e.g., 102, 104, 106, 108) whereby each cell is a symbolic representation of the physical terrain or geographical region covered by communication network equipment commonly known as cell sites or base stations (e.g., 110, 112, 114).
  • Each base station has system equipment comprising radio equipment (i.e., transmitter, receiver, modulator, demodulator) that are used to transmit and/or receive communication signals between a base station and a user equipment.
  • the system equipment can also be located at places other than base stations.
  • the term "user” hereinafter is used interchangeably with the term “subscriber” to indicate an entity (i.e., person, facility or a combination thereof) who is allowed access (when possible) to the communication system. Access to the communication system is the ability of a subscriber to make use of the resources (e.g., system equipment, communication channels) of the communication system.
  • the user equipment e.g., 140 in cell 104) is typically a cellular phone or any other communication equipment that is used by a subscriber of a communication system.
  • the user equipment can be a wireless portable computer or a pager.
  • the system equipment further comprises processing equipment for retrieving information being carried by the communication signals and for implementing procedures based on communication protocols.
  • a communication protocol is a set of procedures or processes that dictate how communications between users of the communication system are to be initiated, maintained and terminated.
  • the communication protocol also dictates the communications between a user and system equipment.
  • Communication protocols are part of well known and established standards (e.g., IS-95A, IS-95B, IS-2000) that are followed by operators of communication systems.
  • each user communicates with a base station via a wireless communication link.
  • a wireless communication link For example in cell 104, user 140 communicates with base station 114 via communication link 156.
  • each wireless communication link comprises several communication channels.
  • CDMA Code Division Multiple Access
  • the communication link comprises an Access channel, a Paging channel and a Traffic channel.
  • the Access channel is a channel through which user equipment transmits protocol information to a base station.
  • Protocol signals (some of which are discussed infra .) carry the protocol information.
  • the protocol information is information used by the system equipment operate and/or control the communication system.
  • a user requesting access to the communication system is allowed to use the communication system after various protocol information have been exchanged between the system equipment (i.e., a base station) and the user equipment.
  • the system equipment identify the user as a subscriber of the system, find resources (e.g., communication channels, base station equipment) that can be made available to the user and allow the user to use (transmit/receive information) such resources in accordance with the protocol being followed by the communication system.
  • resources e.g., communication channels, base station equipment
  • the Paging channel is a channel through which system equipment (e.g., base station) broadcast protocol information to users of the communication system.
  • the traffic channel is the channel used by the users to communicate with each other or with the system.
  • the information conveyed through the traffic channel is, for example, voice, data, video, facsimile information or any other information typically conveyed by users of communication systems.
  • the traffic channel consists of two channels: the first channel is called the reverse link through which users transmit information which information is received by the base station (or other system equipment); the second channel is called the forward link through which the base station (or other system equipment) transmits information to a user.
  • Each user has a forward link and a reverse link assigned by the communication system.
  • any communication channel within which signals are only transmitted from user equipment to system equipment is referred to as an "uplink.” Conversely, any communication channel within which signals are transmitted only from system equipment to user equipment is referred to as a “downlink.”
  • uplink any communication channel within which signals are transmitted only from system equipment to user equipment
  • downlink any communication channel within which signals are transmitted only from system equipment to user equipment.
  • some CDMA systems also have a pilot channel that is used to assist a user to request and obtain access to the communication system.
  • the pilot channel is a downlink channel through which the system equipment broadcast a pilot signal that covers a certain area (e.g., cell area) of the communication system.
  • the pilot signal serves as a sort of beacon signal that advertises the existence of the base station for any user who wants access to the communication system.
  • the pilot signal is typically a system defined carrier signal; that is, the pilot signal is typically a signal of a single frequency, f c .
  • a user initiates a request for access to the communication system by transmitting a protocol signal called a probe signal; thus the probe is an uplink signal.
  • the probe signal is typically also a signal of a certain frequency.
  • the probe has two portions: the first portion is called the preamble which is typically a string of "0" bits or a string of "1" bits; the second portion is a message portion containing protocol information.
  • the preamble is the portion of the probe that allows the base station (or other system equipment) to detect the probe.
  • the system equipment In response to the detection of the probe signal, the system equipment, after a certain time period, transmit an "acknowledge” (ACK) signal to the user equipment indicating to the user equipment that the probe signal has been detected.
  • ACK acknowledgenowledge
  • the ACK and CAM signals are downlink protocol signals within which are protocol information or messages.
  • the ACK message is followed (after a certain time delay) by a Channel Assignment Message (CAM).
  • CAM also transmitted by the system equipment
  • there is an Early ACK message which is another type of an "acknowledge" signal.
  • the probe signal is not detected by the system equipment because the power (or amplitude) of the probe signal received by the system equipment is attenuated due to various effects experienced by the communication link.
  • the adverse effects are caused by well known adverse channel conditions such as amplitude attenuation, phase jitter and frequency translation.
  • the user equipment transmits the probe signal repeatedly until it receives the ACK message.
  • the power of the probe signal is increased by a system defined amount hereinafter referred to as " ⁇ .”
  • a graph of the power of the probe signal versus time is shown in FIG. 2. Each probe is transmitted after a certain time interval where ⁇ is a system defined fixed time interval and is a time interval of random length for the i th probe signal.
  • the first transmitted probe has an amplitude of P 1
  • the second probe has an amplitude of P 2
  • the third probe has an amplitude of P 3 and so on.
  • P 0 is a system defined (i.e., network provider defined) nominal probe power that is used as an initial probe power.
  • the user equipment monitors its allocated traffic channel (i.e., its forward link) to test frames conveyed over the traffic channel by the system equipment. Once the user equipment determines that two consecutive frames have been received without any errors, it transmits a preamble signal (via the traffic channel reverse link) to the system equipment indicating that the protocol signals ACK, CAM and test frames were received successfully. It should be noted that the user equipment contains well known error detection schemes or techniques (implemented in hardware or software or both) that detect whether a received frame contains errors.
  • the preamble once received by the system equipment, is an indication that the user equipment has obtained the proper traffic channel and is ready to convey information over such channel.
  • the ACK and CAM protocol signals are not detected; that is, various channel conditions cause the protocol signals to be attenuated to a point where they cannot be detected by the user equipment. It is likely that the channel conditions that affected adversely (e.g., attenuation of power) the probe signal will have the same or similar adverse effects on the downlink protocol signals (i.e., ACK and CAM) as both the probe signal and the ACK and CAM signals propagate through the same environment. Unlike the probe signal, however, the power of the CAM and ACK signals are not adjusted to compensate for signal power degradation.
  • the user equipment is unable to complete the protocol procedure and, after a defined time period, the user equipment starts the entire procedure once again.
  • the ability of a user to obtain access to a communication system is lessened because many times the uplink protocol signals are not detected by the user equipment.
  • What is therefore needed is a method for adjusting the power of the protocol messages to increase the likelihood that such messages are detected by the user equipment and to reduce the time it takes a user to gain access to the communication system.
  • the present invention provides a method for adjusting at least one characteristics of a protocol signal transmitted by equipment of a wireless communication system to increase the likelihood that such a protocol signal is detected by other equipment of the communication system.
  • One particular characteristic of a protocol signal is the power of such a signal.
  • the equipment Prior to transmission, the equipment adjusts the power of the protocol signal based on adjustments made to another protocol signal which has already been detected. Because the protocol signals propagate through similar environments, it is likely that any adverse conditions experienced and overcome by the detected protocol signal will also affect the protocol signal to be transmitted. Therefore, when the adjustments made to the protocol signal to be transmitted are based on the adjustments made to the detected protocol signal, there is an increased likelihood that the protocol signal to be transmitted will be detected.
  • the detected protocol signal is a probe signal which has a message portion wherein information about adjustments made to the probe signal are stored by the equipment. Once the probe signal is received and detected by system equipment, the adjustment information is retrieved from the probe's message portion. The adjustment information is used to adjust at least one characteristic of a protocol signal to be transmitted by the system equipment to the user equipment thereby increasing the likelihood that such a protocol signal will be detected by the user equipment. In this embodiment, the protocol signal to be transmitted is in response to the detected probe signal.
  • the protocol signal to be transmitted is either an ACK signal and/or a CAM (or Early ACK for IS-2000 standard) signal transmitted in response to a detected probe signal.
  • the present invention provides a method for adjusting at least one characteristic of a protocol signal to be transmitted by equipment of a communication system based on adjustments made to at least one characteristic of a detected protocol signal transmitted by another equipment.
  • the adjustments thus made tend to increase the likelihood that the protocol signal to be transmitted will be detected by the other equipment.
  • One particular characteristic of a protocol signal is the power of such a signal.
  • the equipment monitors a channel of the communication system for a protocol signal.
  • the equipment receives and detects a protocol signal from other equipment and retrieves adjustment information from the detected protocol signal. The adjustment information was inserted in the detected protocol signal by the other equipment prior to transmission.
  • the protocol signal to be transmitted by the equipment is adjusted based on the retrieved information and is transmitted to the other equipment thus increasing the likelihood that such a signal will be detected by the other equipment.
  • the adjusted protocol signal is being transmitted in response to the detected protocol signal transmitted by the other equipment.
  • the method of the present invention will be described in terms of a CDMA wireless cellular communication system that complies with the IS-95A or IS-95B or IS-2000 standards.
  • the protocol signal to be transmitted is either an ACK signal (Early ACK for IS-2000 systems) or a CAM signal or both.
  • the protocol signal from which the adjustment information is retrieved is the probe signal.
  • the signal to be transmitted is in response to the detected signal.
  • the method of the present invention also included situations where the signal to be transmitted is not in response to the detected.
  • other signal characteristics e.g., amplitude, frequency content, phase
  • the adjustments can be made to more than one signal characteristic.
  • the method of the present invention is described in terms of user equipment transmitting a protocol signal within which information about at least one adjustment made to at least one characteristic (e.g., power) of the signal is stored.
  • the method of the present invention is also described in terms of system equipment detecting the protocol signal carrying the adjustment information. The system equipment retrieve the adjustment information and adjust at least one characteristic of a protocol signal to be transmitted thereby increasing the likelihood that such a protocol signal will be detected.
  • step 300 the user equipment is activated (e.g., cell phone is switched on).
  • step 302 the user equipment monitors the Paging channel and the pilot channel for a pilot signal and other protocol signals.
  • the other protocol signals comprise information such as the Access Parameter Message and the System Parameter Message used by the user equipment to obtain access to the communication system.
  • step 304 if the protocol signals are not detected the method of the present invention returns to step 302 to continue to monitor the Paging channel.
  • the method of the present invention moves to step 306.
  • the user equipment transmits the probe signal wherein a probe number is inserted in the message portion of the probe signal.
  • the probe power is adjusted as per equation (1).
  • a portion of the probe message (e.g., a certain number of bits) can be reserved exclusively for the probe number. Such a portion can be established as part of the standard (i.e., IS-95A and/or IS-95B).
  • the probe number represents one type of adjustment information. Other types of adjustment information relating to other signal characteristics can be used.
  • step 308 if the user equipment has received and detected a responding protocol signal (i.e., the ACK protocol signal followed by the CAM protocol signal), the method of the present invention moves to step 310 where the protocol procedure is completed appropriately as per the IS-95 standard. If the ACK protocol signal is not detected by the user equipment within a period of time (defined by the standard), the method of the present invention moves to step 312 where the user equipment increases the probe power by a ⁇ amount, increases i by 1 and stores the new value for i in the defined portion of the probe message. The method of the present invention returns to step 302 and 304, and after detecting monitoring the access channel for certain protocol signals and detecting such signals, transmits the adjusted probe signal along with the new probe number once again.
  • a responding protocol signal i.e., the ACK protocol signal followed by the CAM protocol signal
  • the user equipment increases the probe number by 1 and again stores it in a portion of the probe message.
  • the probe number also represents the number of times the probe signal has been adjusted.
  • step 400 the system equipment are monitoring the Access channel for a probe signal.
  • step 402 the system equipment receive and detect a probe signal whose message has a portion that has a probe number stored therein.
  • the probe number represents adjustment information.
  • the probe number is retrieved by the system equipment.
  • step 404 the probe number is decreased by 1 and the resulting number (i.e., i -1) is multiplied by ⁇ where ⁇ represents a power amount defined by the network provider. It should be noted that ⁇ is defined by the network provider and thus may or may not equal to ⁇ , the incremental power amount used to adjust the power of the probe signal.
  • the product i.e., ( i -1) ⁇ ⁇ , is the amount by which an initial power value of the next protocol signal (i.e., the ACK protocol signal) to be transmitted is adjusted in response to the probe signal.
  • the ACK signal has a nominal power of p 0
  • the power of the ACK signal to be transmitted is increased by an amount equal to ( i -1) ⁇ ⁇ .
  • the nominal power of the ACK signal is thus adjusted based on the adjustment information (i.e., probe number) carried by the detected probe signal.
  • the new power, p new of the ACK signal is (2) p 0 + ( i -1) ⁇ ⁇ .
  • step 406 the adjusted protocol signal, p new , is transmitted.
  • the CAM signal is transmitted after a certain time period defined by the IS-95 standard.
  • the power of the CAM signal is adjusted in the same manner as that of the ACK signal (or Early ACK signal).
  • step 408 the system equipment wait for the proper response from the user equipment. If the appropriate response is received within a defined time period, the method of the present invention moves to step 410 where the protocol procedure is completed. If the appropriate response was not received, i.e., no preamble signal received over the traffic channel from the user equipment, the method of the present invention moves to step 412 in which all resource allocations made are canceled and the system equipment again begins the procedure by monitoring the Access channel as per steps 400 and 402.
  • step 404 a new power value is calculated as per equation (2) which power value is based on the latest adjustment information received by the system equipment.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Radio Relay Systems (AREA)
  • Transmitters (AREA)
EP00307590A 1999-09-14 2000-09-04 Power control method for broadcast messages Withdrawn EP1085675A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US396825 1995-03-02
US39682599A 1999-09-14 1999-09-14

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EP1085675A2 true EP1085675A2 (en) 2001-03-21

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EP00307590A Withdrawn EP1085675A2 (en) 1999-09-14 2000-09-04 Power control method for broadcast messages

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EP (1) EP1085675A2 (ja)
JP (1) JP2001119341A (ja)
KR (1) KR20010050393A (ja)
CN (1) CN1288340A (ja)
AU (1) AU5655600A (ja)
BR (1) BR0003997A (ja)
CA (1) CA2317295A1 (ja)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009034187A1 (de) 2009-07-22 2011-02-03 Gmbu E.V., Fachsektion Dresden Waschstabile photokatalytische Textilbeschichtung
DE102010009002A1 (de) 2010-02-24 2011-08-25 Gesellschaft zur Förderung von Medizin-, Bio- und Umwelttechnologien e.V., 01454 Anatas-haltiges wasserbasiertes Beschichtungsmittel und dessen Anwendung zur Herstellung von photoaktiven Textilien
US8320951B2 (en) 2004-03-12 2012-11-27 Alcatel Lucent Power sharing process in cellular network architecture

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030119452A1 (en) * 2001-10-19 2003-06-26 Samsung Electronics Co., Ltd. Apparatus and method for controlling transmission power of downlink data channel in a mobile communication system supporting MBMS
DE602007008065D1 (de) * 2006-01-11 2010-09-09 Qualcomm Inc Kommunikationsverfahren und vorrichtung zum senden von prioritätsinformationen über bakensignale
KR20140053531A (ko) * 2012-10-26 2014-05-08 삼성전자주식회사 방송수신장치 및 그 제어방법

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8320951B2 (en) 2004-03-12 2012-11-27 Alcatel Lucent Power sharing process in cellular network architecture
DE102009034187A1 (de) 2009-07-22 2011-02-03 Gmbu E.V., Fachsektion Dresden Waschstabile photokatalytische Textilbeschichtung
DE102010009002A1 (de) 2010-02-24 2011-08-25 Gesellschaft zur Förderung von Medizin-, Bio- und Umwelttechnologien e.V., 01454 Anatas-haltiges wasserbasiertes Beschichtungsmittel und dessen Anwendung zur Herstellung von photoaktiven Textilien

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Publication number Publication date
KR20010050393A (ko) 2001-06-15
AU5655600A (en) 2001-03-15
CN1288340A (zh) 2001-03-21
CA2317295A1 (en) 2001-03-14
JP2001119341A (ja) 2001-04-27
BR0003997A (pt) 2001-04-17

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